Polyglycerol compounds are well known materials. They are made by the condensation reaction of glycerin. The resulting products are polar and posses several un-reacted hydroxyl groups. The number of glycerin molecules condensed in the reaction is referred to as the degree of polymerization (DP). The condensation reaction run between two glycerin molecules produces water as a byproduct. U.S. Pat. No. 5,721,305 issued Feb. 24, 1998 to Eshuis, et al. entitled Polyglycerol production teaches how polyglycerol is made.
U.S. Pat. No. 3,936,391 issued Feb. 3, 1976 to Gabby entitled “Hydrated polyglycerol Ester Composition” teaches a polyglycerol ester emulsifier is prepared by heating a polyglycerol ester containing 3 to 10 glycerol units and a 1 to 2 saturated fatty acyl ester groups containing 16 to 20 carbon atoms, glycerol and water at a temperature of 125 to 135° F. The heat is maintained until a homogeneous paste-like consistency is imparted thereto.
U.S. Pat. No. 5,674,475 issued Oct. 7, 1997 to Dahms entitled “Emulsifier Composition based on Polyglycerol Ester” teaches an emulsifier composition of a mixture of polyglycerol fatty acid esters and the lactylate of a fatty acid or its salt. This emulsifier is used to manufacture a wide range of different oil in water emulsions.
U.S. Pat. No. 1,424,137 issued July 1922 to Weisberg, entitled “Polyglycerol Resins” discloses a polyglycerol ester of an aromatic dibasic acid used in shellac. This patent, imported herein by reference, addresses solid resins made in solvent. While lacking the critical control of cross-linking and producing a hard rather than a soft ester, this patent shows the state of the art in resins.
Still another U.S. Pat. No. 7,638,116, issued Dec. 29, 2009 by LaVay et al. entitled “Polyglycerol dimer polyester resins” discloses a polyglycerol dimer resin of a polyglycerol containing 3 to 10 repeat units cross-linked by dimer acid. While lacking the critical control of cross-linking and functionalization by fatty groups, this patent shows the state of the art of polyglycerol dimer polyesters.